| Message ID | 20220212171449.3000885-1-keescook@chromium.org (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 2618a0dae09ef37728dab89ff60418cbe25ae6bd |
| Headers | show |
| Series | etherdevice: Adjust ether_addr* prototypes to silence -Wstringop-overead | expand |
Hello: This patch was applied to netdev/net-next.git (master) by David S. Miller <davem@davemloft.net>: On Sat, 12 Feb 2022 09:14:49 -0800 you wrote: > With GCC 12, -Wstringop-overread was warning about an implicit cast from > char[6] to char[8]. However, the extra 2 bytes are always thrown away, > alignment doesn't matter, and the risk of hitting the edge of unallocated > memory has been accepted, so this prototype can just be converted to a > regular char *. Silences: > > net/core/dev.c: In function ‘bpf_prog_run_generic_xdp’: net/core/dev.c:4618:21: warning: ‘ether_addr_equal_64bits’ reading 8 bytes from a region of size 6 [-Wstringop-overread] > 4618 | orig_host = ether_addr_equal_64bits(eth->h_dest, > skb->dev->dev_addr); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > net/core/dev.c:4618:21: note: referencing argument 1 of type ‘const u8[8]’ {aka ‘const unsigned char[8]’} > net/core/dev.c:4618:21: note: referencing argument 2 of type ‘const u8[8]’ {aka ‘const unsigned char[8]’} > In file included from net/core/dev.c:91: include/linux/etherdevice.h:375:20: note: in a call to function ‘ether_addr_equal_64bits’ > 375 | static inline bool ether_addr_equal_64bits(const u8 addr1[6+2], > | ^~~~~~~~~~~~~~~~~~~~~~~ > > [...] Here is the summary with links: - etherdevice: Adjust ether_addr* prototypes to silence -Wstringop-overead https://git.kernel.org/netdev/net-next/c/2618a0dae09e You are awesome, thank you!
diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h index 2ad71cc90b37..92b10e67d5f8 100644 --- a/include/linux/etherdevice.h +++ b/include/linux/etherdevice.h @@ -134,7 +134,7 @@ static inline bool is_multicast_ether_addr(const u8 *addr) #endif } -static inline bool is_multicast_ether_addr_64bits(const u8 addr[6+2]) +static inline bool is_multicast_ether_addr_64bits(const u8 *addr) { #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64 #ifdef __BIG_ENDIAN @@ -372,8 +372,7 @@ static inline bool ether_addr_equal(const u8 *addr1, const u8 *addr2) * Please note that alignment of addr1 & addr2 are only guaranteed to be 16 bits. */ -static inline bool ether_addr_equal_64bits(const u8 addr1[6+2], - const u8 addr2[6+2]) +static inline bool ether_addr_equal_64bits(const u8 *addr1, const u8 *addr2) { #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64 u64 fold = (*(const u64 *)addr1) ^ (*(const u64 *)addr2);
With GCC 12, -Wstringop-overread was warning about an implicit cast from char[6] to char[8]. However, the extra 2 bytes are always thrown away, alignment doesn't matter, and the risk of hitting the edge of unallocated memory has been accepted, so this prototype can just be converted to a regular char *. Silences: net/core/dev.c: In function ‘bpf_prog_run_generic_xdp’: net/core/dev.c:4618:21: warning: ‘ether_addr_equal_64bits’ reading 8 bytes from a region of size 6 [-Wstringop-overread] 4618 | orig_host = ether_addr_equal_64bits(eth->h_dest, > skb->dev->dev_addr); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ net/core/dev.c:4618:21: note: referencing argument 1 of type ‘const u8[8]’ {aka ‘const unsigned char[8]’} net/core/dev.c:4618:21: note: referencing argument 2 of type ‘const u8[8]’ {aka ‘const unsigned char[8]’} In file included from net/core/dev.c:91: include/linux/etherdevice.h:375:20: note: in a call to function ‘ether_addr_equal_64bits’ 375 | static inline bool ether_addr_equal_64bits(const u8 addr1[6+2], | ^~~~~~~~~~~~~~~~~~~~~~~ Reported-by: Marc Kleine-Budde <mkl@pengutronix.de> Tested-by: Marc Kleine-Budde <mkl@pengutronix.de> Link: https://lore.kernel.org/netdev/20220212090811.uuzk6d76agw2vv73@pengutronix.de Cc: Jakub Kicinski <kuba@kernel.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> --- include/linux/etherdevice.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)